Actuator and control assembly for retractable landing gears



Oct. 12, 1948. R. M. NARDONE 2,451,109

ACTUATOR AND CONTROL ASSEMBLY FOR RETRACTABLE LANDING GEARS Filed Jan. 28, 1944 5 Sheets-Sheet 1 I N V EN TOR. lZomeoM/uu'dozz BY ATTDRNEY IRE YRAC TI 0/! UNIT Oct. 12, 1948. R. M. NARDONE ACTUATOR AND CONTROL ASSEMBLY FOR RETRACTABLE LANDING GEARS 5 Sheets-Sheet 2 Filed Jan. 28, 1944 INVENTOR. YROmeo MA ardome AT TU/P/VE) Oct. 12, 1948. R. M. NARDONE 2,451,109

ACTUATQR AND CONTROL ASSEMBLY FOR RETRACTABLE LANDING GEARS 5 Sheets-Sheet 3 Filed Jan. 28, 1944 Oct. 12, 1948. R. M. NARDONE 2,451,109

ACTUATOR AND CONTROL ASSEMBLY-FOR RETRACTABLE LANDING GEARS Filed Jan. 28, 1944 R A 5 Sheets-Sheet 4 MMzrdoze Mam R. M. NARDONE ACTUATOR AND CONTROL ASSEMBLY FOR Oct. 12, 1948.

RETRACTABLE LANDING GEARS 5 Sheets-Sheet 5 Filed Jan. 28, 1944 wig INVEN TOR. Roma/74mm BY W AND/PAIL) Patented Get. 12, 1948 UNITED STATES PATE'N-T OFFICE ao'rn'aironenn ooNriaoi'. ASSEMBLY FOR RETEAQTABLE EANDING GEARS Romeo MfNardone, Teaneck, N; .L assignor to Bendix Aviation Corporation, Teterboro, N. 5., a corporation of Delaware Application January 28, 1944, Serial No. 520,123

(o1: gee-102) 6 Claims.

1 I The present invention has to do with retractable landing gears and is concerned primarily with an assembly associated therewith for actu-' ating and controlling the raising and lowering movements of the landing gear.

The invention has in view as an important object the provision of a unit which affords a brake.

gear, and a further more detailed object is the provision of mechanical means for applying the brake as the landing gear completes a predetermined run.

Another object or the invention is associated with th feature of the speed limiter. As above pointed out, a brake is employed for controlling the movement of the landing gear. Associated with this brake is a speed-responsivedevice which is effective to apply variable braking eiiects, de-

- pending upon the speed of movementof the landing gear.

A further object is to provide, in operative association with a landing gear, an actuator unit which ordinarily is located at one side of the landing gear, and the unit embodyingthe brake," P

speed limiter and manual release, which is positioned at the opposite side. There is an electrical hook-up between the actuator unit and. the brake in the second unit so as to synchronize the operation of these elements. I

These and other more detailed objects and advantages will in part become apparentand in part be hereinafter stated as the description of the invention proceeds.

For a full and more complete understandingof the invention, reference may be had to the following description and accompanying drawings wherein:

Fig. 1 is an outline of the two units developing their relation to the landing gear;

Fig. 2 is an end elevation of the actuator unit; Fig. 3 is an end elevation of the other unit; I Fig. 4 is a horizontal section through the unit, including the brake, speed limiter'aiid manual release;

I Fig. 5 is a vertical section through the unit of -Fig. 4 being taken about on the plane represented by the line 5--5 of Fig. 4;

Fig. 6 is another vertical section taken about on the plane represented by the line 6-- 6 of Fig. 4;

Fig. 7 is a vertical section through the actuator unit; and

Fig; 8 is a schematic View developing the wiring diagram of the two units. II I I I Referring to the drawing, wherein like refer- ;Ience characters denote corresponding parts, and -particularly to Fig. 1 a hub H, of the landing gear actuating mechanism, rotates through a prescribed are as the gear is retractedor lowered.

ations under power.

The actuator unit A ordinarily causes these oper- This actuator unit is located at one end oi th eII'hubH where instant ""shaft H] (see Fig. 7) extends into the hub to es- "tablish the driving relation.

The second unit B, which embraces'the brake,

'speed limiter and manual release, is positioned on the opposite end of the hub H. The unit B includes a main control shaft "I Ifwhich" is drivably received in a socket in -the hubli in amenner comparable to the connection of the shaft Hl thereto. This shaft H is indicated in dotted lines in Fig. 1 and is developed more'in detail in' Fig. 4.

Referring to Fig.4, the unit' Bdi shown as housed within a casing made 'up of sections l2 and 13 which are pr'ovidedwith compleinental flanges l4 through'which extend bolts -I5 to establish the assembled relation ofthe casing sections.

A disc carrier ii for a friction disc brake has a flange it that is clamped between the flanges ing action and the bolts I 5.

I4 and securely held in position by this clamp- This disc carrier is one element of a friction brake whichwillbe later described in detail.

The casing section l2 includes a ring-like'end wall l8 from which a sleeveflQ extends inwardly. The sleeve l9 carries a pair of bearing assemblies 2i] and 2! which are spaced apart as illustrated,

and these'bearing assemblies receive and support the shaft I l in a usual'manner. I

The inner end of the shaft H has a portion 22 splined to a'second friction brake or disccarrier element 23. The disc carrier 23 is'adapted for sliding movement along the shaft ll. IIIiriterfittingclutch discs 2 are carried by "the carriers n and 2e," and inter fit in a well khown manner.

I The braking effects afforded by the elementsl'l,

23 and 2d, depend upon the degree of engagement of'the discs 25. When the discs on the member disposed-about the rod 33.

IT are free from those on the member 23 there are no braking effects, but the braking effects gradually increase as these discs engage under greater pressure.

Where the splines 22 terminate, the shaft H is reduced in diameter and threaded as shown at 25, and screwed thereon is a spring retaining nut 26. An expansion spring 21' is interposed between the disc carrier 23 and the retainer 26 and normally tends to maintain the discs 24 out of engagement. An abutment ring 28 is carried by the element '23 and engages the disc pack at one end.

A ring 29 is also keyed to the shaft H at the splines 22, and this ring is provided with'a plurality of radially outstanding ears 30 (see Fig. These ears are arranged in pairs and pivotally mounted between each pair is an arm M, which is weighted at its free extremity, as indicated at 32. The opposite extremity of each of the arms ,3l is formed with a cam surface 33, which is in operative engagement with the disc carrier 23.

The ring 29 and weighted arms 31 rotate with the shaft 5 l. The angular position of these arms with respect to the axis of the shaft, will vary depending upon the speed of rotation of the shaft as it affects the weighted ends 32 under centrifugalforce. As the weighted ends 32 move radially outwardly, the engagement of the cam surfaces 33 with the disc carrier 23, moves the latter to the right, as viewed in Figure 4:, and due to the engagement of the abutment ring 28 with the disc pack, causes engagement of the discs 24 to apply the brake. r

The casing section i3 has an end wall 34 formed with a threaded opening 35 into which is screwed a cup-shaped member 36, the bottom of which is formed with an opening through which passes a rod 38. This rod 38 is mounted for reciprocatory movement in a heavy sleeve 3 carried by a plate il) that'is secured to the end wall 34 as by screws 4|.

'Adjacent the outer free end of the rod 38, the latter is formed with a groove G2, which provides a head 43; 'A plurality of ball elements 45 are received in the groove 42 and maintained therein by a ring retaining element 45 which is This ring 45 is provided with a plurality of cam sockets 46 which partially receive balls 41. The latter are also partially received in sockets 48 formed in a fixed ring 4% that is carried by the cup member 35.

VA crank arm 50, Figures 1 and 3, has one end secured to the ring 45, so that swinging of the arm 56 causes rotation of the ring 15. This rotation renders effective the ball cams 4'! on the cam sockets 55 and causes the ring 45 to move outwardly. This outward movement, due to the presence 'of the bearings 54 and their engagement with the head 53. causes a corresponding movement of the rod 38. The inner end of the rod 38 is formed with head 5! and the sleeve 39 is provided with a countersunk recess 52 which receives an expan sion spring 53. This spring 53 engages the head 5! and normally exerts a tendency urging the ca] opening 58, which receives the head 5| of rod 38. The armature 5? is provided with a plurality of recesses 59 which open on to the plate 56. An expansion spring 60 is positioned in each recess 59 and bears against the fixed plate 56.

These springs Gil normally exert a tendency to" Extending upwardly from the casing section 13 is an external ear 62, Figures 1 and 3, and a corresponding ear 63 upstands from the casing section l2. A shaft 64 is journaled in the ears 62 and 63. An arm 65 is drivably carriedby the shaft 5 5 atone end and extends downwardly where its bifurcated end 66 receives a pin 61 on the crank arm 5B. The shaft 64 extends over the landing gear hub H and at this location carries a short arm 68 which is adapted to be engaged by a control'element or pin 69 carried by the hub I-I.

' When the pin 59 engages the short arm 68 the shaft 54 is rotated. This in turn swings the arm 85 which causes swinging movement of the crank arm 50. If either of the arms or 65 has been operated to manually release the brake and thus permit lowering of the landing gear, when the landing gear approaches its lower limit of travel I and because of the positioning of thepin 69, the

latter will affect the shaft 5 3 to'cause rotation thereof in direction causing movement of the rod 38 inwardly under the influence of the spring 53 and which movement in turn provides for the application 'of the brake by springs 60.-

Referring to Fig. 7, the various mechanisms of the unit A are housed within a casing made up of end section lfl; intermediate section 1| and inner end section 12, the several sections being fastened together by the screws represented at The inner end section 12 is provided with a bearing assembly it in which is journaled the output shaft 10. On the inner side of the bearing assembly 74, the output shaft H3 carries a pinion 15. A gear train G, drivably connects the pinion rod 38' inwardly. Thus, outward movement of the rod 38 is against the influence of the spring 53.

Disposed about the sleeve 39, and positioned within the leasing section; is a" solenoid 55. This solenoid is supported by a cylindrical member 55 carried within the sleeve section l3 and which in turn carries a ring-like plate 56. This plate '56 is in fixed position with respect to the casing.

An armature 5? is formed with a central coni- 7 5 with another pinion l6 keyed to a screw shaft H. Threaded on this screw shaft l'l is a traveling member 18, which is adapted to alternately engage spaced limit switches 19 and 80.

The shaft 11, traveling member 18 and limit switches 19 'and'8fl are located in the upper portion of the intermediate casing section 1i and constitute the means fordetermining the length of a prescribed cycle of operation; As the member l8 moves from one limit switch to the other, the output shaft l6 will rotate through a predetermined number of revolutions. f

Splined for sliding movement onthe output shaft Ill is a movable jaw clutchelement 8| having teeth 82*which are adapted to 'interfit 'and' engage with correspondingiteethion an axially fixed rotative jaw clutch element 83. 7 .An. ex- 7 pansion spring 9 is interposed between the jaw clutch elements Hand 83. Thelatter is formed to the casing section H, and meshing therewith, as well as with a sun gear 85, are a plurality of planet gears 81 that are carried by the carrier 84. The sun gear 86 is in turn formed as an integral part of a planet gear carrier 88 carrying planet gears 85 which mesh with the orbit gear 85 and a sun gear 90, the latter being carried by a shaft 8|.

An electric motor M includes a drive shaft 92. Driving connection between the shafts E2 and 9.! is by means of the tongue and slot connection 8. The friction clutch mechanism is illustrated, described, and claimed in the patents of Nardone, Patent No. 2,408,992 and Patent No. 2,391,333,

and it is, therefore, believed unnecessary to here go into a detailed discussion of this friction clutch. This clutch mechanism is referred to in its entirety by the reference character F. The purpose of this friction clutch mechanism is to limit the torque on the shaft .Hl. Obviously, load conditions may vary and this friction clutch will accommodate the overloading by maintaining peak limiting torque value.

A pair of concentric solenoids 93 and 94 are disposed about the movable jaw element 8! and either is adapted to cause movement of the jaw element into clutch engaging position.

The motor M includes a pair of field coils 95 and 96 (see Fig. 8). The delivery of current to the field coils 95 and 96 is controlled by solenoid switches 91 and 98. When one coil is energized, the drive shaft 92 of the motor M is driven in one direction, but when the other coil is energized, the rotation is in the opposite direction.

In referring to the Wiring diagram of Fig. 8, it is important to note that the solenoid 54 of the unit B is shown as tied in with the electrical circuit for the actuator unit A. Thus, when the actuator unit is started into operation, the solenoid 54 is energized to release the brake of the unit B and permit of free rotation of the shaft H, which, of course, means that no impediment is offered to the operation of the landing gear. However, whenever the actuator unit A is stopped, the solenoid 54 is de-energized, whereupon the springs 60 move the armature '51 inwardly to cause application of the brake and hold the shaft H against rotation.

While a substantially comprehensive description of the operation of the actuator unit is set forth in either of the above-identified Nardone applications, it may be noted that when the toggle switch is thrown to either raise or lower the landing gear, the proper field coil of the motor M is energized to cause rotation in the required direction. At the same time, one of the solenoids 93 or 94 is also energized to move the movable clutch element 8| into engagement with the clutch element 83.

Thus, the motor is started in operation and the drive to the out-put shaft I is established. As this output shaft l0 rotates through a prescribed cycle, the gear train G turns the screw shaft 1! and causes the traveling member 18 to move into engagement with one of the contact switches. This engagement terminates the run, during which the motor M is stopped, the jaw clutch elements 8! and 83 are disengaged, and the brake of unit B is applied.

While only one embodiment of the invention is hereinbefore set forth, it is to be clearly understood that the invention is not to be limited to the exact construction illustrated and described because various modifications of these details may be provided in putting the invention into practice within the purview of the appended claims.

Whatis claimed is:

1. The combination for aircraft landing gear, of a hub having limited landing and retracting movement about its aXis and carrying brake control means, a driven shaft having one and extending into one end of the hub, clutch jaw means including a driving clutch jaw at the other end of said driven shaft aligned therewith and a clutch jaw on said driven shaft, said jaws being normally forced to declut'ched position relative to each other, a reversible motor, motor speed reducing means and torque limiting friction clutch means connected between said motor and said driving jaw, electrically operable means operative in either direction .of operation of said motor to actuate said clutch jaws to clutched relation to each other, and means comprising a brake shaft extending into the opposite end of said hub for cooperation with said driven shaft, a fixed support, a cooperating support rot-a tive with and axially movable relative to said brake shaft, a friction disc clutch pack having axially movable discs non-rotatively supported by said fixed support and rotatively carried by said rotative support, respectively, centrifugal means carried by said rotative support at one end of said pack for adjusting the friction between said discs, disc pressin means at the other end of said pack normally biased to press the discs together, electror-esponsive means for operating said disc pressing means against said bias to friction release position, movable means operative independently of said electroresponsive means for operating said disc pressing means against said bias to friction release position and normally influenced to inactive position, and means capable of manual operation for actuating said movable means against said influence to actuate said disc pressing means against said bias and adapted for operation by said brake control means to release said movable means and said die pressing means.

:2. The combination for aircraft landing gear, of a hub having limited landing and retracting movement about its axis and carrying brake control means, a driven shaft having one end extending into one end of the hub, clutch jaw means including a driving clutch jaw at the other end of said driven shaft aligned therewith and a clutch jaw on said driven shaft, said jaws being normally forced to declutched position relative to each other, a reversible motor, motor speed reducing means and torque limiting means con nee-ted between said motor and said driving clutch jaw, electric-ally operable means operative in either direction of operation of said motor to actuate said clutch jaws to clutched relation to each other, and means comprising a brake shaft extending into the opposite end of said hub for cooperation with said driven shaft, a fixed support, variable friction means having cooperating friction means on said brake shaft and said support, respectively, centrifugal means carried by said brake shaft for adjusting the friction of said friction means, a second means for adjusting the friction of said friction means and normally biased to increase the friction thereof, electroresponsive means for operating said second means against said bias to friction release position, movable mean-s operative independently of said electroresponsive means for operating aid second means against said bias to friction release position and normally influenced to inactive position, and means capable of manual operation for actuating said movable means against said influence to actuate second means against said bias and adapted for operation by said brake control means to release said movable means and said second,

means. i

3. The combination for aircraft landing gear, of brake control means having limited reverse movements in accordance with landing and retracting movements of the gear, driving and driven members, a motor, motor speed reducing and torque limiting means connected between said motor and said driving member, means including electrically operable means for connecting said members to, and disconnecting the same from, each other, and means. comprising a brake shaft cooperating With said driven member, variable friction means cooperating between said brake shaft and a fixed element of the gear, means for adjusting the friction of said friction means in accordance with the rate of rotation of said brake shaft, second means for adjusting the friction of said friction means, electroresponsive means for operating said second means to friction release position, movable means operative inde pendently of said electroresponsive means for operating said second means to friction release position, and means capable of manual operation for actuating said movable means to operate said second means to friction release position and adapted for operation by said brake control means to release said movable means and said second means to cause said friction adjusting means to increase its friction.

4. The combination for retractable aircraft gear having means movable in accordance with exelectroresponsive means adapted to release said braking means near the beginning of said extend-1 ing movement, and means capable of manual operation for similarly releasing said braking means and operable by said brake control means at said position to cause said braking means to brake said rotatable element.

5.-The combination of means having limited reverse movements, brake controlimeans movable in accordance with and adaptedto effect its control function at a position near the end'of one of said movements, an element movable in :ac-

cordance with said movements, means normally braking said element, means adapted to adjust the braking effect of said braking means in ac-' cordance with the rate of movement of said element, power operated means adapted to release said braking meansinear the beginning. of said one movement, and means capable of manual operation for similarly releasing said' braking means and operable by said brake control means at said position to cause said braking means to ment, power operated means adapted to release said braking means near the beginning of said one movement, and means capable of operation independently of said power operated means for similarly releasing said braking means and oper able by said brake control meansat said position to cause said braking means to brakesaid element. 1 V V ROMEO M. NARDONE.

REFERENCES CITED The following references are of record in the file of this patent: I

UNITED STATES PATENTS Number Name 7 Date 821,629 Eifel May 29, 1906 1,245,532 I Townsend et a1 Nov. 6, 1917 2214;,80'7 Buckley Sept. 17,1940 2,314,019 Shaw Mar. 16, 1943 i 2,385,459 Nelson et a1 Sept. 25,1945 2,387,799

Leland Oct. 30, 1945 

